[lldb] [llvm] [lldb-dap] Add unknown request handler (PR #181109)
Sergei Druzhkov via llvm-commits
llvm-commits at lists.llvm.org
Thu Feb 12 01:27:44 PST 2026
https://github.com/DrSergei created https://github.com/llvm/llvm-project/pull/181109
Added unknown request handler to avoid crash. Returning error in this case looks better than stopping entire debug session.
```
0. Program arguments: /home/sergei/llvm-project/build/bin/lldb-dap
#0 0x0000603918a0ed92 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/home/sergei/llvm-project/build/bin/lldb-dap+0x6ed92)
#1 0x0000603918a0c29f llvm::sys::RunSignalHandlers() (/home/sergei/llvm-project/build/bin/lldb-dap+0x6c29f)
#2 0x0000603918a0c3ec SignalHandler(int, siginfo_t*, void*) Signals.cpp:0:0
#3 0x00007b487ba45330 (/lib/x86_64-linux-gnu/libc.so.6+0x45330)
#4 0x00007b487ba9eb2c __pthread_kill_implementation ./nptl/pthread_kill.c:44:76
#5 0x00007b487ba9eb2c __pthread_kill_internal ./nptl/pthread_kill.c:78:10
#6 0x00007b487ba9eb2c pthread_kill ./nptl/pthread_kill.c:89:10
#7 0x00007b487ba4527e raise ./signal/../sysdeps/posix/raise.c:27:6
#8 0x00007b487ba288ff abort ./stdlib/abort.c:81:7
#9 0x00007b487bea5ff5 (/lib/x86_64-linux-gnu/libstdc++.so.6+0xa5ff5)
#10 0x00007b487bebb0da (/lib/x86_64-linux-gnu/libstdc++.so.6+0xbb0da)
#11 0x00007b487bea5a55 std::unexpected() (/lib/x86_64-linux-gnu/libstdc++.so.6+0xa5a55)
#12 0x0000603918a27cdd (/home/sergei/llvm-project/build/bin/lldb-dap+0x87cdd)
#13 0x00006039189c6b7d main (/home/sergei/llvm-project/build/bin/lldb-dap+0x26b7d)
#14 0x00007b487ba2a1ca __libc_start_call_main ./csu/../sysdeps/nptl/libc_start_call_main.h:74:3
#15 0x00007b487ba2a28b call_init ./csu/../csu/libc-start.c:128:20
#16 0x00007b487ba2a28b __libc_start_main ./csu/../csu/libc-start.c:347:5
#17 0x00006039189c80d5 _start (/home/sergei/llvm-project/build/bin/lldb-dap+0x280d5)
```
>From be4803b9bb0a465346bb8a6afbd36478d26b2e37 Mon Sep 17 00:00:00 2001
From: Sergei Druzhkov <serzhdruzhok at gmail.com>
Date: Thu, 12 Feb 2026 12:24:58 +0300
Subject: [PATCH] [lldb-dap] Add unknown request handler
---
.../test/tools/lldb-dap/dap_server.py | 8 ++++++
.../launch/TestDAP_launch_unknown_request.py | 25 +++++++++++++++++++
lldb/tools/lldb-dap/CMakeLists.txt | 1 +
lldb/tools/lldb-dap/DAP.cpp | 14 +++++------
lldb/tools/lldb-dap/DAP.h | 2 ++
lldb/tools/lldb-dap/Handler/RequestHandler.h | 9 +++++++
.../Handler/UnknownRequestHandler.cpp | 19 ++++++++++++++
.../lldb-dap/Protocol/ProtocolRequests.h | 5 ++++
.../gn/secondary/lldb/tools/lldb-dap/BUILD.gn | 1 +
9 files changed, 76 insertions(+), 8 deletions(-)
create mode 100644 lldb/test/API/tools/lldb-dap/launch/TestDAP_launch_unknown_request.py
create mode 100644 lldb/tools/lldb-dap/Handler/UnknownRequestHandler.cpp
diff --git a/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/dap_server.py b/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/dap_server.py
index fdccc9eae9fe4..7bbad52147747 100644
--- a/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/dap_server.py
+++ b/lldb/packages/Python/lldbsuite/test/tools/lldb-dap/dap_server.py
@@ -1677,6 +1677,14 @@ def request_testGetTargetBreakpoints(self):
}
return self._send_recv(command_dict)
+ def request_unknown(self):
+ command_dict = {
+ "command": "unknown",
+ "type": "request",
+ "arguments": {},
+ }
+ return self._send_recv(command_dict)
+
def terminate(self):
self.send.close()
if self._recv_thread.is_alive():
diff --git a/lldb/test/API/tools/lldb-dap/launch/TestDAP_launch_unknown_request.py b/lldb/test/API/tools/lldb-dap/launch/TestDAP_launch_unknown_request.py
new file mode 100644
index 0000000000000..8a0f8b4a80590
--- /dev/null
+++ b/lldb/test/API/tools/lldb-dap/launch/TestDAP_launch_unknown_request.py
@@ -0,0 +1,25 @@
+"""
+Test lldb-dap launch request.
+"""
+
+from lldbsuite.test.decorators import expectedFailureWindows
+import lldbdap_testcase
+
+
+class TestDAP_launch_unknown_request(lldbdap_testcase.DAPTestCaseBase):
+ """
+ Tests handling of unknown request.
+ """
+
+ @expectedFailureWindows(
+ bugnumber="https://github.com/llvm/llvm-project/issues/137599"
+ )
+ def test(self):
+ program = self.getBuildArtifact("a.out")
+ self.build_and_launch(program)
+
+ response = self.dap_server.request_unknown()
+ self.assertFalse(response["success"])
+ self.assertEqual(response["body"]["error"]["format"], "Unknown request")
+
+ self.continue_to_exit()
diff --git a/lldb/tools/lldb-dap/CMakeLists.txt b/lldb/tools/lldb-dap/CMakeLists.txt
index 8566c663fcc06..1bb7a2e498b9b 100644
--- a/lldb/tools/lldb-dap/CMakeLists.txt
+++ b/lldb/tools/lldb-dap/CMakeLists.txt
@@ -64,6 +64,7 @@ add_lldb_library(lldbDAP
Handler/StepOutRequestHandler.cpp
Handler/TestGetTargetBreakpointsRequestHandler.cpp
Handler/ThreadsRequestHandler.cpp
+ Handler/UnknownRequestHandler.cpp
Handler/VariablesRequestHandler.cpp
Handler/WriteMemoryRequestHandler.cpp
diff --git a/lldb/tools/lldb-dap/DAP.cpp b/lldb/tools/lldb-dap/DAP.cpp
index b76b05c5d1459..0a0d3c3903409 100644
--- a/lldb/tools/lldb-dap/DAP.cpp
+++ b/lldb/tools/lldb-dap/DAP.cpp
@@ -849,15 +849,11 @@ bool DAP::HandleObject(const Message &M) {
auto handler_pos = request_handlers.find(req->command);
dispatcher.Set("client_data",
llvm::Twine("request_command:", req->command).str());
- if (handler_pos != request_handlers.end()) {
+ if (handler_pos != request_handlers.end())
handler_pos->second->Run(*req);
- return true; // Success
- }
-
- dispatcher.Set("error",
- llvm::Twine("unhandled-command:" + req->command).str());
- DAP_LOG(log, "error: unhandled command '{0}'", req->command);
- return false; // Fail
+ else
+ unknown_request_handler->Run(*req);
+ return true; // Success
}
if (const auto *resp = std::get_if<Response>(&M)) {
@@ -1577,6 +1573,8 @@ void DAP::RegisterRequests() {
RegisterRequest<VariablesRequestHandler>();
RegisterRequest<WriteMemoryRequestHandler>();
+ unknown_request_handler = std::make_unique<UnknownRequestHandler>(*this);
+
// Custom requests
RegisterRequest<CompileUnitsRequestHandler>();
RegisterRequest<ModulesRequestHandler>();
diff --git a/lldb/tools/lldb-dap/DAP.h b/lldb/tools/lldb-dap/DAP.h
index 34d6a29b3c110..f2e1162eb3a61 100644
--- a/lldb/tools/lldb-dap/DAP.h
+++ b/lldb/tools/lldb-dap/DAP.h
@@ -482,6 +482,8 @@ struct DAP final : public DAPTransport::MessageHandler {
llvm::StringMap<std::unique_ptr<BaseRequestHandler>> request_handlers;
/// @}
+ std::unique_ptr<BaseRequestHandler> unknown_request_handler;
+
/// Event threads.
/// @{
void ProgressEventThread();
diff --git a/lldb/tools/lldb-dap/Handler/RequestHandler.h b/lldb/tools/lldb-dap/Handler/RequestHandler.h
index 9feb636fd5c28..4b4f1435e7acb 100644
--- a/lldb/tools/lldb-dap/Handler/RequestHandler.h
+++ b/lldb/tools/lldb-dap/Handler/RequestHandler.h
@@ -658,6 +658,15 @@ class WriteMemoryRequestHandler final
Run(const protocol::WriteMemoryArguments &args) const override;
};
+class UnknownRequestHandler final
+ : public RequestHandler<protocol::UnknownArguments,
+ protocol::UnknownResponseBody> {
+public:
+ using RequestHandler::RequestHandler;
+ static llvm::StringLiteral GetCommand() { return "unknown"; }
+ llvm::Error Run(const protocol::UnknownArguments &args) const override;
+};
+
} // namespace lldb_dap
#endif
diff --git a/lldb/tools/lldb-dap/Handler/UnknownRequestHandler.cpp b/lldb/tools/lldb-dap/Handler/UnknownRequestHandler.cpp
new file mode 100644
index 0000000000000..c576256a48265
--- /dev/null
+++ b/lldb/tools/lldb-dap/Handler/UnknownRequestHandler.cpp
@@ -0,0 +1,19 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "DAPError.h"
+#include "Protocol/ProtocolRequests.h"
+#include "RequestHandler.h"
+#include "llvm/Support/Error.h"
+
+using namespace lldb_dap;
+using namespace lldb_dap::protocol;
+
+llvm::Error UnknownRequestHandler::Run(const UnknownArguments &args) const {
+ return llvm::make_error<DAPError>("Unknown request");
+}
diff --git a/lldb/tools/lldb-dap/Protocol/ProtocolRequests.h b/lldb/tools/lldb-dap/Protocol/ProtocolRequests.h
index 28c9f48200e0c..91fc2a4db6f57 100644
--- a/lldb/tools/lldb-dap/Protocol/ProtocolRequests.h
+++ b/lldb/tools/lldb-dap/Protocol/ProtocolRequests.h
@@ -1312,6 +1312,11 @@ struct StackTraceResponseBody {
};
llvm::json::Value toJSON(const StackTraceResponseBody &);
+/// Arguments for unknown request.
+using UnknownArguments = EmptyArguments;
+/// Response to unknowns request.
+using UnknownResponseBody = VoidResponse;
+
} // namespace lldb_dap::protocol
#endif
diff --git a/llvm/utils/gn/secondary/lldb/tools/lldb-dap/BUILD.gn b/llvm/utils/gn/secondary/lldb/tools/lldb-dap/BUILD.gn
index 896da7df95bb1..edcbc5e31f4f1 100644
--- a/llvm/utils/gn/secondary/lldb/tools/lldb-dap/BUILD.gn
+++ b/llvm/utils/gn/secondary/lldb/tools/lldb-dap/BUILD.gn
@@ -68,6 +68,7 @@ static_library("lib") {
"Handler/StepOutRequestHandler.cpp",
"Handler/TestGetTargetBreakpointsRequestHandler.cpp",
"Handler/ThreadsRequestHandler.cpp",
+ "Handler/UnknownRequestHandler.cpp",
"Handler/VariablesRequestHandler.cpp",
"Handler/WriteMemoryRequestHandler.cpp",
"InstructionBreakpoint.cpp",
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